Aluminum is the most abundant metal on earth, and electronic devices that are based on aluminum have the advantage of being inexpensive to produce. An aluminum-based redox couple involves in three-electron transfer during electrochemical charge/discharge reactions, and when applied to an energy storage device, it could provide a greater energy storage capacity. Furthermore, aluminum has low flammability and redoxability, meaning that an aluminum-ion battery might offer significant safety improvements.
The electrolyte composition employed in some traditional metal-ion batteries (such as an aluminum-ion battery) may include ionic liquid. For example, some aluminum-ion batteries employ an electrolyte composition including aluminum chloride and imidazolium chloride and exhibit good electrochemical reversibility. Since the imidazolium chloride has a high cost and the ratio of imidazolium chloride to aluminum chloride for forming a eutectic system is strict, the yield of the aluminum-ion battery employing the same is limited.
Therefore, the industry needs a novel electrolyte composition to solve the problems mentioned above.
According to embodiments of the disclosure, the disclosure provides an electrolyte composition and a metal-ion battery employing the same. The electrolyte composition includes a metal halide, an organic compound and a halogen-containing salt. In particular, the organic compound can be nitrogen-containing compound, sulfur-containing compound, or a combination thereof. The halogen-containing salt can have a structure represented by Formula (I):[Ca+]i[X−]j  Formula (I), wherein C can be IA element, IIA element, IIIA element, IVA element, VA element, VIA element, transition metal, pyrrolium, pyrrolinium, pyrrolidinium, pyridinium, ammonium, imidazolium, indazolium, pyrimidinium, azaannulenium, azathiazolium, benzimidazolium, benzofuranium, benzotriazolium, borolium, cholinium, cinnolinium, diazabicyclodecenium, diazabicyclononenium, diazabicyclo-undecenium, dithiazolium, furanium, guanidinium, indolinium, indolium, morpholinium, oxaborolium, oxaphospholium, oxazinium, oxazolium, iso-oxazolium, oxathiazolium, pentazolium, phospholium, phosphonium, phthalazinium, piperazinium, piperidinium, pyranium, pyrazinium, pyrazolium, pyridazinium, quinazolinium, quinolinium, iso-quinolinium, quinoxalinium, selenozolium, sulfonium, tetrazolium, iso-thiadiazolium, thiazinium, thiazolium, thiophenium, thiuronium, triazadecenium, triazinium, triazolium, iso-triazolium, or uronium; X can be fluorine, chlorine, bromine, or iodine; a=j/i; i can be 1, 2, 3, or 4; and j can be 1, 2, 3, 4, 5, or 6. The molar ratio of the metal halide to the organic compound can be greater than 2; the molar ratio of the metal halide to the halogen-containing salt can be greater than 2; and, the metal halide is distinct from the halogen-containing salt.
According to embodiments of the disclosure, the disclosure also provides a battery. The metal-ion battery includes a positive electrode, a separator, a negative electrode, and an electrolyte. The negative electrode and the positive electrode are separated from each other by the separator; and, the electrolyte composition is disposed between the positive electrode and the negative electrode.
A detailed description is given in the following embodiments with reference to the accompanying drawings.